The present invention relates, in general, to an apparatus to neutralize landmines and, in particular, to an apparatus to neutralize landmines with high power microwaves
Canadian Forces soldiers deployed abroad during the early 1990""s suffered a large number of landmine accidents, many involving vehicles that were struck by low metal content landmines buried in roads. Existing detection technology at that time, primarily based on metal detection, had failed to detect landmines which were located in the path of the vehicles.
A mine neutralisation study in 1995 assumed that neutralisation activities would follow a robot detection vehicle. That study considered that, for the short term, a mini-flail could be used in concert with an array of shaped charges to neutralize detected landmines. It recommended, however, that the potential of using High Power Microwaves (HPM) to neutralize landmines be investigated.
W. J. Graham, in an internal research report looked into the feasibility of a focussed microwave array for detecting and neutralising buried landmines. A focussed array consists of a series of flat elements with precision-machined slots from which microwave radiation is emitted. The neutralisation concept was based on the ability of the system to concentrate sufficient microwave energy on a small patch of ground approximately 25-30 cm2 in size to reach a field intensity over 100W/cm2. Neutralisation of the landmine was intended to be obtained through melting the plastic components of the pressure plate in order to disable the functioning mechanism rather than the initiation of a high order detonation.
An article in The Mail on Sunday on Jun. 15, 1997 entitled xe2x80x9cWill a British microwave stop the worldwide horror of the landmine?xe2x80x9d indicated that if they could design a radar antenna which could concentrate microwaves into a tight beam there would be a reasonable chance of setting off a spark that could detonate a landmine from a distance.
An article xe2x80x9cElectromagnetic Scattering by an Object Buried in Soilxe2x80x9d by S. Kashyap et al appeared in the ANTEM ""98 Symposium on Antenna Technology and Applied Electromagnetics examined the scattering of electromagnetic wave by an object buried in the soil and their effects.
A German Patent DE19744794 by Samland Thomas which was published on Nov. 15, 1998 is directed to a mine clearance method using a high power focussed microwave beam by detection of reflected radiation in the microwave or IR range. Another U.S. Pat. No. 6,343,534 by S. Khanna et al also teaches the detection of landmines using high power microwaves. In this US Patent, a thermal signature of the soil surface is obtained in real time as the soil is being irradiated forming an interference pattern at the soil surface and also further thermal signatures are obtained after irradiation resulting from thermal conduction from a mine heated by the microwaves.
It is an object of the present invention to provide an apparatus to neutralize landmines using high power microwaves and to provide a design that prevents damage to the microwave generator when a landmine is detonated by the apparatus.
An apparatus to neutralize landmines using high power microwaves, according to one embodiment of the present invention, comprises an antenna mounted on a vehicle at an angle to the vertical such that a microwave beam is directed to a surface of soil near the vehicle when a microwave generator is energized, the microwave generator and a power source being mounted on said vehicle with a waveguide being connected between the microwave generator and a feed horn for the antenna, at least one plug that is transparent to said microwaves being positioned in said waveguide to prevent any blast wave produced by a detonated mine from propagating inside of said waveguide towards the microwave generator.